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Algae  Plant-like protists  Contain chlorophyll and carry out photosynthesis  Many are highly mobile  Scientists often disagree with their placement, particularly those that are very similar to plants  There are 7 major phyla according to their cellular characteristics

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Chlorophyll  One way of classifying algae is with the pigments it contains  Algae lives in water  There is limited light in this environment  Different types of chlorophyll (a, b, c) absorb different wavelengths of light  As a result, algae can use more than red and violet wavelengths of light

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Accessory Pigments  Absorb light at different wavelengths than chlorophyll  These pigments also produce energy for the organism  They appear to be colours other than green

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Phylum Euglenophyta (Euglenophytes)  Contain two flagella but no cell wall  Contain chloroplasts  Contain reddish pigment concentrated in one area – known as a eyespot  Heterotrophic when sunlight is unavailable  Contain a cell membrane called a pellicle  This allows them to crawl when they can’t swim

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Ecology  Common in salt and fresh water  Some can cause serious problems  They are the basis of the food chain in aquatic environments  They are grouped with other marine organisms called phytoplankton (small aquatic living things at the bottom of oceans)

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Algal Blooms  Algae grows abundantly where sewage is discharged  They help recycle waste materials into usable molecules  When a lot of sewage accumulates, so do algal populations  These are referred to as blooms  Algae eventually dies and depletes the water of oxygen

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Phylum Rhodophyta (Red Algae)  Contain chlorophyll a and reddish accessory pigments called phycobilins (absorb blue light)  Can live deep in the ocean  Highly adaptable to different temperatures  Help in the formation of coral reefs

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Phylum Phaeophyta (Brown Algae)  Contain chlorophyll a and c as well as brown pigment, fuocoxanthin  Dark yellow to brown colour  Largest and most complex of the algae  Mostly marine, cool coastal water  Kelp is the most common example  Rockweed or seaweed too

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Phylum Chlorophyta (Green Algae)  Share many characteristics with plants  Photosynthetic pigments and cell wall composition  Found in fresh and salt water as well as moist land environments  Most live entire lives as single cells – unicellular although a few types are multicellular

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Ecology of Algae  Major food source for organisms in oceans  Called the “grasses” of the seas  They produce much of the world’s oxygen  Rich in vitamin C and iron  Many of the products we use have algae in its ingredients